BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//http://molbio.princeton.edu///NONSGML kigkonsult.se iCalcreator 2.10.15//
METHOD:PUBLISH
BEGIN:VEVENT
UID:20150802T162404EDT-5411FobISv@http://molbio.princeton.edu/
DTSTAMP:20150802T202404Z
DESCRIPTION:Special Seminar\nSpeaker\nKC Huang\n\nStanford University\n\nKC
Huang was an undergraduate Physics and Mathematics major in Page House at
Caltech\, and spent a year as a Churchill Scholar at Cambridge University
working with Dr. Guna Rajagopal on Quantum Monte Carlo simulations of wat
er cluster formation. He received his PhD from MIT working with Prof. John
Joannopoulos on electromagnetic flux localization in polaritonic photonic
crystals and the control of melting at semiconductor surfaces using nanos
cale coatings. During a short summer internship at NEC Research Labs\, he
became interested in self-organization in biological systems\, and moved o
n to a postdoc with Prof. Ned Wingreen in the Department of Molecular Biol
ogy at Princeton working on the relationships among cell shape detection\,
determination\, and maintenance in bacteria. His lab is currently situate
d in the departments of Bioengineering and Microbiology&amp\;Immunology at
Stanford\, and his current interests include cell division\, membrane org
anization\, cell wall biogenesis\, and collective motility of bacterial co
mmunities. His lab is a force to be reckoned with in pickup basketball.\n&
nbsp\;\n\n\nSeminar Topic\nStructural Dynamics Reveal New Mechanisms of Fe
edback Between Cell Geometry and Intracellular Organization\nThe assembly
of protein filaments drives many cellular processes\, from nucleoid segreg
ation\, growth\, and division in single cells to muscle contraction in ani
mals. In eukaryotes\, shape\, motility\, and cytokinesis are regulated thr
ough cycles of polymerization and depolymerization of actin and microtubul
e cytoskeletal networks. In bacteria\, the actin homolog MreB and the tubu
lin homolog FtsZ form filaments that coordinate the cell-wall synthesis an
d division machineries\, respectively. A fundamental challenge in cell bio
logy is to link the structural properties of these filaments to cellular b
ehaviors and morphogenesis. We have used all-atom molecular dynamics simul
ations to reveal the nucleotide-dependent polymer mechanics of these cytos
keletal filaments. For FtsZ\, our simulations predict that small changes a
t the monomer-monomer interface result in a large hinge-opening leading to
filament bending upon GTP hydrolysis\, which was confirmed solving the st
ructure of an FtsZ-GDP filament by X-ray crystallography. Next\, I will de
monstrate that similarly subtle modifications to the interprotofilament in
terface in microtubules due to acetylation are responsible for perturbing
the quinary structure of the microtubules enervating touch receptor neuron
s in C. elegans\, leading to a defect in mechanosensation. We observe that
MreB exhibits actin-like polymerization-dependent structural changes\, wh
erein polymerization induces flattening of MreB subunits\, and hydrolyzed
polymers favored a straighter conformation. Taken together\, our results p
rovide molecular-scale insight into the diversity of structural states and
the relationships among polymerization\, hydrolysis\, and filament proper
ties within the actin and tubulin families. I will close by demonstrating
a novel curvature-sensing strategy of the protein SpoVM\, which initialize
s the formation of the spore coat in Bacillus subtilis. Taken together\, o
ur results highlight the expanding utility of molecular dynamics to link t
he atomic scales of protein function and the cellular scales of behavior.
\nResearch Lab\nwhatislife.stanford.edu/LoCo.html\nAudience\nFree and open
to the university community and the public
DTSTART:20140115T120000
DTEND:20140115T130000
LOCATION:Schultz Lab\, 107 (Washington Road \, Princeton)
SUMMARY:KC Huang (Stanford University)
END:VEVENT
END:VCALENDAR